This invention relates in general to tubing for flowing gas lasers and in particular, to the use of porous ceramic materials for the walls of the tubing.
Waveguide capillary lasers exhibit high optical gains and saturation intensities for certain flowing gas systems, as for example, flowing gas CO.sub.2 systems. However, axial flow systems give rise to a linearly varying pressure distribution which causes highly variable gains and saturation intensities along the tube axis. For narrow bore tubes which are made of dense ceramic materials, fast flow or long capillaries, this axial pressure differential becomes large thereby limiting the optimum pressure, for gain, to a relatively short length of the tube axis. This establishes realistic limits in scaling such amplifier tubes to long lengths.